Strip duplicate leading slashes before both routing and handling requests

Global.scala

import play.api._
import play.api.mvc._
import scala.concurrent.Future

object RewrittenRequestHeader {
  def rewrite(header: RequestHeader): RequestHeader = {
    if (header.path.startsWith("//")) {
      val newPath = header.path.substring(1)
      RewrittenRequestHeader(newPath, header)
    } else {
      header
    }
  }
}

case class RewrittenRequestHeader(val path: String, delegate: RequestHeader) extends RequestHeader {
  def id = delegate.id
  def tags = delegate.tags
  def uri = delegate.uri
  def method = delegate.method
  def version = delegate.version
  def queryString = delegate.queryString
  def remoteAddress = delegate.remoteAddress
  def headers = delegate.headers
}

object StripLeadingSlash extends Filter {

  def apply(next: (RequestHeader) => Future[SimpleResult])(header: RequestHeader): Future[SimpleResult] = {
    next(RewrittenRequestHeader.rewrite(header))
  }

}

object Global extends WithFilters(StripLeadingSlash) {

  override def onRouteRequest(header: RequestHeader): Option[Handler] = {
    super.onRouteRequest(RewrittenRequestHeader.rewrite(header))
  }

}